The new challenge to the United States administration's tariff policy reflects the increasing discontent that is being aggravated by the inflation caused by energy price hikes due to the Middle East crisis triggered by Washington and Tel Aviv. While the litigation initiated by a coalition of 25 states, mostly Democrat-led, against the Section 301 tariffs on Monday underscores the growing partisan divide, businesses oppose the tariffs primarily because of the rising costs imposed on the economy.

Those hoping the judges of the US Court of International Trade hearing the lawsuit brought by the states will simply strike down the tariffs should temper their expectations. Unlike the earlier International Emergency Economic Powers Act case, in which the US president was judged to have exceeded his authority, the US administration enters the dispute in a stronger position.

READ MORE: 25 US states sue Trump administration over Section 301 tariffs

This time the US administration has imposed tariffs under Section 301 of the Trade Act of 1974, which expressly authorizes the president to impose tariffs in response to "unfair" foreign trade practices. The government's argument is that it has acted within the limits of the authority the US Congress delegated. The court is therefore unlikely to spend much time debating whether tariffs make sound economic policy. It will instead ask two narrower questions: Did Congress authorize tariffs of this breadth, imposed in this manner?

Historically, Section 301 investigations have focused on specific countries, specific conduct and proportionate remedies. Section 301 was never conceived as a blank check for redesigning global trade policy. Congress enacted it as a targeted enforcement mechanism against identifiable "unfair" foreign practices, not as a universal tariff authority affecting nearly all US imports.

The new tariffs, covering imports from 59 economies and the European Union on the basis of alleged "forced-labor" concerns, represent a dramatic expansion of the statute's traditional reach. The plaintiffs therefore argue that Section 301 has become a substitute vehicle for policies the US Supreme Court has already rejected. As they claimed, the US administration has merely exchanged one statutory label for another while pursuing the same sweeping tariff regime.

If the "forced-labor" investigations are found merely to provide legal cover for replacing invalidated IEEPA tariffs, the US administration's position will become more vulnerable. So whether the courts are willing to scrutinize the factual basis of those "forced-labor" findings may prove just as important as interpreting the statute itself.

Judges should exercise their own independent judgment when interpreting Section 301 rather than accepting the Office of the US Trade Representative's reading of it. And the court's increasingly influential Major Questions Doctrine requires clear congressional authorization before government agencies exercise powers of vast economic and political significance. A tariff regime affecting almost the entire US import market plainly raises questions of that magnitude.

So the administrative record assumes unusual importance. The court will examine whether the USTR followed the Congress-prescribed procedures — investigations, public hearings, factual findings and reasoned explanations — or whether tariff rates were chosen first and justified later.

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Tariffs remain taxes, and taxes ultimately fall on someone. The US administration's dealmaking tool has become an instrument of economic coercion directed as much at US businesses as foreign governments. The litigation is likely to take years reaching the Federal Circuit and perhaps the US Supreme Court. In that time, the tariffs will continue to tax the US economy unless they are revoked.

While many blame US tariff policies for the rise of unilateralism and protectionism, the deeper concern lies in the political and institutional soil from which those impulses have grown. The real issue is a Congress that has increasingly tolerated the expansion of executive authority for partisan interests. Courts can police the boundaries of executive power, but only Congress can redraw them. Whether the polarized legislature can still rise above partisan divisions and vested interests to reclaim its constitutional authority over trade will ultimately determine whether the US' political system can overcome its challenges through self-correction.